The present invention relates to an aircraft flying at high altitude, and to a method of getting the aircraft onto station, and also to applications thereof.
In the context of the present invention, “high altitude” means an altitude which is higher both than the altitude of civilian air links and the altitude of earth's cloud ceiling. The atmosphere situated at such high altitude is referred to below as the “high” atmosphere.
Over the last few years numerous studies and proposals, usually of a theoretical nature, have been made concerning the design and use of an aircraft, e.g. an airplane, a balloon, or a motorized parachute, for the purpose of going from the ground into the high atmosphere, e.g. into the stratosphere, and remaining there permanently, in order to perform specific processing or operations. By way of illustration, mention can be made of the proposals described in documents WO 96/12643 and WO 95/32893.
Very numerous operations can be envisaged such as observing the earth, telecommunications, scientific research, i.e. operations which are usually performed by satellites. Unfortunately, satellites are extremely expensive and can be considered only for major users, generally States or collections of States.
In contrast, an aircraft flying at high altitude could be affordable for small territorial entities, such as local or regional government organizations or companies of smaller size. Such an aircraft flying at high altitude does not require a launch rocket and, furthermore, unlike a satellite, since it remains in the atmosphere it can make use of components that are not qualified for use in space. This explains why such an aircraft is economically of interest.
Nevertheless, in spite of that, the high altitude aircraft solutions that have been envisaged or proposed are unfeasible, both economically and even technically. In particular:                because of their high weight, and thus significant weight/power ratio, the aircraft that have been proposed are generally too heavy to remain at high altitude on a permanent basis, in particular, the energy supplied by batteries and possibly by solar cells often remains inadequate;        in addition, the energy storage capacities proposed are generally insufficient to provide power over night; and        other energy sources, such as transmitting energy by microwaves from the ground, are too complex and expensive and they are also harmful for the environment.        